Sympathetic Skin Response (SSR) is a simple investigation pe ıformed to evaluate the sudomotor functions of postganglionic, unmyelinated sympathetic fibers. It is a noninvasive test used in studying particularly the axon functions of unmyelinated fibers in neripheral neuropathies. SSR is considered to be pathologic when it is absent since amplitute and latency are within normal ranges so long as it is present. Abnormalities of SSR are no correlated to the clinical findings of disautonomy. The reason for this is that SSR is designed to investigate especially sympathetic skin fibers and that disautonomy does not test parasympathetic or motorsympathetic fibers which mediate the majority of clinical symptoms. We studied SSR, a useful and noninvasive test in the early diagnosis of disautonomy, in 26 (11 female, 15 male) patients in whom disease was detected, which could be the cause of clinical neuropathy, or neuropathy was detected neurophysiologically, 7 with pernicious anemia and 19 with vitamin B12 deficiency, aged 20-70 (mean 45) and we were not able to obtain SSR in only 4 of them. While there were findings which support neuropathy of neurophysiloogically axonal type in 2 of these patients, neurophysiological finding were normal in the remaining 2 patients.